1. Field of the Invention
The present invention relates, in general, to an apparatus and method for inspecting the electrodes of a battery, and, more particularly, to an apparatus and method for inspecting the electrodes of a battery, which inspects the arrangement state of anodes and cathodes in the battery in a non-destructive manner (using X-rays).
2. Description of the Related Art
Recently, the development of mobile devices such as mobile phones or notebook computers and the practicalization of hybrid vehicles have increased the need for secondary batteries such as lithium-ion batteries or nickel-hydrogen batteries. Accordingly, explosions attributable to the shorts or the heating of secondary batteries have become a hot issue, and thus the importance of inspecting batteries to provide safe and reliable batteries has currently increased.
Referring to FIG. 1, a battery 10 may include a hollow casing 13 having the shape of a rectangular parallelepiped, and anodes 11 and cathodes 12 installed in the casing 13. The anodes 11 and the cathodes 12 may be formed in such a way that a plurality of plate-shaped anodes 11 and a plurality of plate-shaped cathodes 12 are paired, and the respective pairs are stacked in the casing 13. The anodes 11 and the cathodes 12 may be alternately stacked.
It is feared that if the anodes 11 are formed to extend to be longer than the cathodes 12 when the anodes 11 and the cathodes 12 are stacked, lithium which is one of materials constituting the battery 10 is separated from the longer anodes at the time that the battery 10 is used, and thus the battery 10 may be shorted or ignition attributable to heat may occur. Due to this, it is very important to form the cross-sectional areas of the anodes 11 so that they are smaller than those of the cathodes 12. Further, it is very important to stack the anodes 11 and the cathodes 12 in a stepped manner so that the peripheral sides of the anodes 11 do not deviate from the peripheral sides of the cathodes 12. In order to inspect the state of the arrangement of the anodes 11 and the cathodes 12, that is, the step difference, X-ray fluoroscopy which is a non-destructive method has been used.
As shown in FIG. 2, a conventional apparatus for inspecting a battery employs a scheme for determining images detected by a first detector 3 by radiating a first X-ray beam 2a from a first X-ray source (source part) 2 along the first and second longitudinal sides of the battery 10 and images detected by a second detector 3′ by radiating a second X-ray beam 2a′ from a second X-ray source (source part) 2′ along the first and second lateral sides of the battery 10, and then inspecting the arrangement state of the electrodes of the battery 10.
The above-described apparatus for inspecting the battery uses a method of conducting inspection by transmitting X-rays along the lateral and longitudinal directions of the battery. Accordingly, a problem arises in that if the length for which the X-rays pass through the battery exceeds a predetermined length, accurate images cannot be obtained due to the scattering of frequencies, and the reliability of inspection is deteriorated.